be an escape from the insurance implications. If you make such drastic modifications to your car you will have to at some point inform your insurance company anyway. (or risk voiding coverage in an incident). As far as the weight difference goes, and how thorough your TT conversion project would be, chances are you'd be adding a lot of the weight back onto the NA as well.
Z-Jay Vice President - Edmonton Z Car Club 93 300ZX TT - Stage VI